1. Field of the Invention
The present invention relates to a RF system implemented on a single silicon-based chip and a method for manufacturing the same.
2. Description of the Related Art
With the recent rapid development of communication technologies, there is a need for corresponding development of RF (Radio Frequency) device technologies. In particular, due to multi-functionalization, there is a demand for miniaturization and integration of wireless communication terminals such as mobile phones. For this reason, nowadays, micro-machining of electronic devices through MEMS (Micro Electrical Mechanical System) technologies is performed as practiced by those of ordinary skill in the art.
Individual electronic devices processed in this manner are integrated on a LTCC (Low Temperature Co-fired Ceramic) substrate or a MLB (Multi-Layer Board) substrate formed by laminating plural PCBs (Printed Circuit Boards) to implement a RF system. The RF system implemented on such a LTCC substrate or MLB substrate forms a predetermined circuit therein through an inductor, a capacitor or the like implemented in a two-dimensional structure, and various active devices such as a LNA (Low Noise Amplifier), PA (Power Amplifier), or the like and RF MEMS devices such as a filter, switch, duplexer or the like which are three-dimensional devices are formed on top of the RF system.
The above-mentioned RF system is formed with a separate protective film for protecting the three-dimensional RF MEMS devices, in which no device is formed in the protective film. For this reason, there is a limit in integrating and miniaturizing such a RF system.
In addition, there is a disadvantage in that the size of the RF system is increased because various active devices and RF MEMS devices are two-dimensionally arranged on the top side of the LTCC substrate or MLB substrate.
Furthermore, the RF MEMS devices are formed through a silicon process, whereas the LTCC board is formed through a LTCC process in which ceramic and glass materials are mixed and fired. Therefore, in order to implement a RF system on such a LTCC substrate, there is a demand to form RF MEMS devices through a silicon process, to form a LTCC substrate by performing a LTCC process, and then to bond the RF MEMS to the LTCC board. Meanwhile, in order to implement a RF system on a MLB substrate, a MLB process is performed to form a MLB substrate, in which process plural PCBS, each of which is formed with a predetermined circuit pattern, are laminated and then drilled to form interlayer electric interconnections. Then, RF devices formed through a silicon process are bonded to the MLB substrate. Because different kinds of processes are required to implement a RF system, the manufacturing processes of such a RF system are difficult to perform and the manufacturing costs thereof are increased.
For this reason, various research has recently been proposed to implement such a RF system through the same kinds of processes such as a silicon process.